JP5586920B2 - Method for manufacturing flexible semiconductor device - Google Patents

Description

The present invention relates to a method for manufacturing a flexible semiconductor device.

Note that in this specification, a semiconductor device refers to all devices that can function by utilizing semiconductor characteristics, and display devices, semiconductor circuits, and electronic devices using liquid crystal, electroluminescence (EL), and the like are all semiconductor devices. It is.

In recent years, the development of semiconductor device manufacturing technology has been remarkable, and attention has been focused especially on thinning and flexibility.

As a method for manufacturing a flexible semiconductor device, a semiconductor element such as a thin film transistor (TFT) is manufactured on a base material such as a glass substrate or a quartz substrate, and then the semiconductor element is transferred from the base material to another base material (for example, a flexible base material). A technology for transposing has been developed. In order to transfer the semiconductor element to another base material, a step of separating the semiconductor element from the base material used when the semiconductor element is manufactured is necessary.

Examples of a method for making a semiconductor device, in particular, a light emitting device flexible by a peeling process include the following.

The first method is a method of forming an EL layer after peeling and transposition. For example, a peeling assisting resin serving as a support is applied to the upper surface of the TFT substrate on which the peeling layer is formed. Next, an exfoliation trigger is put, and the substrate used in manufacturing the TFT is exfoliated. Subsequently, a flexible substrate is attached to the peeling surface, and the peeling assisting resin is removed. Next, an EL layer is formed above the TFT and sealing is performed.

The second method is a method of forming electrodes, partition walls, EL layers, and the like on the release surface after peeling. For example, a peeling assisting resin serving as a support is applied to the upper surface of the TFT substrate on which the peeling layer is formed. Next, an exfoliation trigger is put, and the substrate used in manufacturing the TFT is exfoliated. Subsequently, a contact hole is formed in the peeling surface, and an indium tin oxide (ITO) film is formed so as to be electrically connected to the drain of the TFT, and an electrode is formed by patterning. Thereafter, a partition wall or an EL layer is formed, and sealing is performed by attaching a film or the like. When this method is used, a light emitting device in which a film is attached to the lower surface and a peeling assisting resin is formed on the upper surface is obtained.

The third method is a method of peeling after forming an electrode, an EL layer, a peeling assisting resin, and the like.

The first method requires application and removal of the peeling assisting resin, which increases the number of steps. The second method requires a photolithography process at least three times (contact hole formation, ITO patterning, partition wall formation) on a flexible substrate, and therefore, technical hurdles are high. Therefore, compared with the first and second methods, the third method has a smaller number of steps and can be said to be a method suitable for mass production.

As a method for peeling a semiconductor element from a base material used in manufacturing a semiconductor element typified by a light-emitting element, there is a method in which a peeling layer is provided and the semiconductor element is peeled from the peeling layer as a starting point. First, a release layer is provided on a substrate, and a semiconductor element film is formed thereon. Thereafter, the semiconductor element film is peeled from the peeling layer by applying a physical force. Peeling is performed in this way to make the semiconductor element flexible.

For example, Patent Document 1 describes a peeling technique using laser ablation as follows. A separation layer made of amorphous silicon or the like is provided on the substrate, and a layer to be peeled made of a thin film element is provided on the separation layer, and the layer to be peeled is adhered to the transfer body by the adhesive layer. The separation layer is ablated by laser light irradiation, thereby causing separation of the separation layer.

Patent Document 2 describes a technique for performing peeling with a physical force such as a human hand. In Patent Document 2, a metal layer is formed between a substrate and an oxide layer, and peeling is performed at the interface between the oxide layer and the metal layer by utilizing weak bonding at the interface between the oxide layer and the metal layer. As a result, the layer to be peeled and the substrate are separated.

In the case of peeling by a physical force such as a human hand, it is necessary to bend the peeled layer in order to peel the peeled layer from the substrate starting from the peeled layer. The layer to be peeled formed in contact with the peeling layer is a thin film on which a semiconductor element including a thin film transistor (TFT), a wiring, an interlayer film, and the like is formed, and is very brittle with a thickness of about 10 μm. When bending stress is applied to the semiconductor element, film peeling and cracking are likely to occur in the layer to be peeled, and this often causes a problem that the semiconductor element is destroyed.

When peeling is performed, a portion having the weakest adhesion among the peeling layer and the peeled layer formed on the substrate is peeled off preferentially. Therefore, in order to start peeling at the interface between the base material and the release layer, the interface between the release layer and the release layer, or inside the release layer without peeling off the laminated film constituting the release layer, In the laminate from the layer to the layer to be peeled, the adhesion between the substrate and the layer to be peeled or the interface between the layer to be peeled and the layer to be peeled needs to be the weakest.

Also, if the release layer is a laminated film, even when the adhesion at the interface of each film constituting the release layer is the weakest, the interface between the substrate and the release layer, the interface between the release layer and the peeled layer, Alternatively, peeling can be performed inside the peeling layer.

However, if the adhesion between the substrate and the release layer, the adhesion between the release layer and the layer to be peeled, or the adhesion between the respective films in the release layer is too weak, the process in which peeling should not be performed ( During the process other than the peeling process, peeling may occur due to the stress of the film. Therefore, it is desirable to have a process in which the release layer maintains a certain level of adhesion until immediately before the peeling step, and by performing some kind of treatment in the peeling step, the adhesiveness of the release layer is artificially reduced.

Japanese Patent Laid-Open No. 10-125931 JP 2003-174153 A

When a semiconductor element is manufactured as a layer to be peeled over a peeling layer via a buffer layer and only the semiconductor element is peeled and transferred, an exfoliation occurs inside the semiconductor element. This is because the adhesiveness between the films in the semiconductor element is weaker than the adhesiveness between the release layer and the buffer layer, and the film in the semiconductor element before the separation between the release layer and the buffer layer to be peeled off. It is because it peels from between the membranes.

There is a possibility that the adhesion between the films in the semiconductor element may be improved by changing the manufacturing method of the semiconductor element, the material used, or applying heat or pressure during the peeling process, but dramatic effects are expected. Absent. For this reason, the technique which weakens the adhesiveness of a peeling layer and a buffer layer is required.

Further, it is necessary to prevent bending stress from being generated in the element due to peeling.

According to one embodiment of the present invention, a semiconductor element formed over a separation layer with a buffer layer interposed therebetween is dissolved in the separation layer using an etchant, thereby reducing the adhesion between the separation layer and the buffer layer. It peels without causing bending stress.

Further, one embodiment of the present invention includes a structure in which a drawing line is formed by laser irradiation so that the etching solution can easily come into contact with the separation layer. In addition, a drawing line is a groove | channel drawn by irradiating a laser beam.

Further, according to one embodiment of the present invention, a film is inserted into a region where the release layer is dissolved by contact with the etching solution, and the film is moved toward a region where the release layer is not dissolved, whereby the semiconductor element is bent. It peels without causing stress.

In one embodiment of the present invention, a peeling layer is formed over a substrate, a buffer layer is formed over the peeling layer, a semiconductor element is formed over the buffer layer, a resin layer is formed over the semiconductor element, and an etching solution is used. The release layer is dissolved, the film is inserted into the dissolved area of the release layer, and the film is moved toward the undissolved area of the release layer, thereby causing no bending stress on the semiconductor element and the substrate. It is characterized by separating the semiconductor element.

According to one embodiment of the present invention, a first buffer layer is formed over a substrate, a separation layer is formed over the first buffer layer, a second buffer layer is formed over the separation layer, and the second buffer layer A semiconductor element is formed thereon, a resin layer is formed on the semiconductor element, the release layer is dissolved using an etching solution, the film is inserted into the dissolved area of the release layer, and the film is not dissolved in the release layer By moving toward the region, the substrate and the semiconductor element are separated without causing bending stress to the semiconductor element.

According to one embodiment of the present invention, a separation layer is formed over a substrate, a buffer layer is formed over the separation layer, a semiconductor element is formed over the buffer layer, a resin layer is formed over the semiconductor element, and the semiconductor element is surrounded As shown, the laser beam is irradiated to form a drawing line in the buffer layer and the resin layer, the peeling layer is dissolved using the etching solution along the drawing line, and the film is inserted into the dissolved area of the peeling layer. The substrate is separated from the semiconductor element without causing bending stress to the semiconductor element by moving the substrate toward the region where the release layer is not dissolved.

According to one embodiment of the present invention, a first buffer layer is formed over a substrate, a separation layer is formed over the first buffer layer, a second buffer layer is formed over the separation layer, and the second buffer layer A semiconductor element is formed thereon, a resin layer is formed on the semiconductor element, and a laser is irradiated so as to surround the semiconductor element, thereby forming drawing lines in the first buffer layer, the second buffer layer, and the resin layer Then, along the drawing line, dissolve the release layer using an etchant, insert the film into the dissolved area of the release layer, and move the film toward the undissolved area of the release layer, thereby creating a semiconductor. The substrate and the semiconductor element are separated without causing bending stress to the element.

When a semiconductor device is manufactured by a conventional method, the entire surface cannot be peeled off. However, the semiconductor element can be formed on a glass substrate, and then the entire surface can be peeled to make it flexible. Further, since the peeling layer is dissolved, the adhesion between the peeling layer and the buffer layer can be weakened, and the semiconductor element can be peeled without causing bending stress. Compared to other peeling processes, the number of steps can be reduced and the alignment step can be facilitated.

Furthermore, by inserting the film into the area where the release layer is dissolved and moving the film toward the area where the release layer is not dissolved, the semiconductor element can be peeled more efficiently without causing bending stress. It can be carried out.

Further, when peeling occurs, a semiconductor element or the like may be destroyed due to the influence of electrostatic discharge (electrostatic discharge, Electro Static Discharge). However, since an etching solution is used, electrostatic discharge destruction can be prevented.

FIG. 6 illustrates Embodiment 1; FIG. 6 illustrates Embodiment 2. 4A and 4B illustrate Embodiment 4 and Example 2. 4A and 4B illustrate Embodiment 4 and Example 2. 4A and 4B illustrate Embodiment 4 and Example 2. 4A and 4B illustrate Embodiment 4 and Example 2. 4A and 4B illustrate Embodiment 4 and Example 2. 4A and 4B illustrate Embodiment 4 and Example 2. 4A and 4B illustrate Embodiment 4 and Example 2. FIG. 6 is a diagram illustrating Example 4; FIG. 6 is a diagram illustrating Example 5; FIG. 6 is a diagram illustrating Example 3;

Embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it is easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below.

(Embodiment 1)
In this embodiment, a method for manufacturing a flexible semiconductor device (particularly, a separation step) will be described.

FIG. 1A shows an element structure before peeling. A peeling layer 101 and a semiconductor element layer 102 are formed over the substrate 100. An ultraviolet curable resin 103 is formed on the semiconductor element layer 102.

The release layer 101 is formed using a metal material. It is preferable to use a material that is soluble in an alkaline solution as the metal material. As an example of such a metal material, tungsten (W), titanium (Ti), aluminum (Al), or tin (Sn) can be used. A thin film of tungsten (W), titanium (Ti), aluminum (Al), or tin (Sn) used as the peeling layer 101 is formed over the substrate 100 by a sputtering method, a plasma CVD method, a coating method, a printing method, or the like. be able to.

The semiconductor element layer 102 includes a thin film transistor (TFT) and the like. The thin film transistor may have any shape and may be manufactured by any method.

Next, the peeling layer 101 is dissolved using the etching solution 104 (FIG. 1B). An alkaline solution is used as the etching solution 104. The alkaline solution is preferably a material that can dissolve (etch) the metal material used for the release layer 101. As an example of such an alkaline solution, an ammonia-hydrogen peroxide mixed solution, TMAH (tetramethylammonium hydroxide), a TMAH-hydrogen peroxide mixed solution, and the like can be given.

In the case where a material (for example, tungsten (W)) that does not dissolve in a single metal but dissolves when oxidized is used as the peeling layer 101, a material in which hydrogen peroxide is mixed in an etching solution may be used. In the case of using a material (for example, aluminum (Al)) that dissolves as a single metal but does not dissolve when oxidized, a material in which hydrogen peroxide is not mixed in an etching solution may be used as the peeling layer 101.

In this manner, by dissolving the peeling layer 101 using the etching solution 104, the adhesion between the substrate 100 and the peeling layer 101 or the adhesion between the peeling layer 101 and the semiconductor element layer 102 can be weakened. Further, since the peeling layer 101 can be completely dissolved, peeling can be performed without bending the manufactured semiconductor element, and the substrate can be reused.

Subsequently, the film 105 is inserted into the region where the release layer 101 is dissolved (FIG. 1C). For the film 105, PEN (polyethylene naphthalate) or the like is used.

Although not shown, actually, when the peeling layer 101 is dissolved using the etching solution 104, the end portions of the semiconductor element layer 102 and the ultraviolet curable resin 103 are lifted by about several millimeters. The film 105 is inserted into the raised portion.

The peeling layer 101 is removed by moving the film 105 toward an area where peeling does not proceed while adding the etching solution 104 to the area where the peeling layer 101 is dissolved (FIG. 1D). By inserting the film 105 and simultaneously performing the dissolution of the peeling layer 101 using the etching liquid 104 and the movement of the film 105, the semiconductor element can be efficiently peeled without causing bending stress.

In the conventional peeling method, even if the peeling layer 101 is dissolved as described in this embodiment mode, when the transfer body 106 using the ultraviolet curable resin 103 as a support and the substrate 100 are separated, the transfer body 106 is used. Needed to bend. In this method, the semiconductor element layer 102 may be destroyed. In this embodiment mode, the etchant 104 is used to insert the film 105 into the region where the release layer 101 is dissolved, and the dissolved release layer is removed and peeled. The etchant 104 is peeled off via the film 105. The peeling layer is further dissolved by coming into contact with a region where peeling of the layer 101 has not progressed. In this manner, the film 105 is moved toward the region where the peeling does not proceed and the peeling layer 101 is removed, so that the peeling can be performed without bending the semiconductor element layer 102.

More efficient peeling can be performed by using both the method of dissolving the peeling layer using an etching solution and the method of peeling by moving the film.

Since it is a method of proceeding peeling while adding an etching solution, electrostatic discharge breakdown can be prevented.

In addition, when the adhesiveness inside the peeling layer is weaker than the adhesiveness between the films in the semiconductor element layer, the peeling can be performed only by the process of moving the film without adding an etching solution. Also in this case, peeling can be performed without causing bending stress to the semiconductor element.

Note that this embodiment can be implemented in appropriate combination with the structures shown in the other embodiments in this specification or the structures shown in the examples.

(Embodiment 2)
In this embodiment, a method for manufacturing a flexible light-emitting device (particularly, a peeling step) will be described.

FIG. 2A shows an element structure before peeling. A peeling layer 201 and an element layer 202 are formed over the substrate 200. The element layer 202 includes a thin film transistor (TFT) and the like. A first electrode 203 and an EL layer 204 are formed over the element layer 202. The EL layer 204 includes a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and the like. A second electrode 205 and an ultraviolet curable resin 206 are formed over the EL layer 204. Note that in this embodiment mode, the first electrode 203 functions as an anode and the second electrode 205 functions as a cathode. In addition, the semiconductor element layer 102 in Embodiment 1 includes the element layer 202, the first electrode 203, the EL layer 204, and the second electrode 205 in this embodiment.

The peeling layer 201 is formed using a metal material. It is preferable to use a material that is soluble in an alkaline solution as the metal material. As an example of such a metal material, tungsten (W), titanium (Ti), aluminum (Al), or tin (Sn) can be used. A thin film of tungsten (W), titanium (Ti), aluminum (Al), or tin (Sn) used as the separation layer 201 is formed over the substrate 200 by a sputtering method, a plasma CVD method, a coating method, a printing method, or the like. be able to.

As the first electrode 203, a metal, an alloy, a conductive compound, a mixture thereof, or the like with a high work function (specifically, 4.0 eV or more) is preferably used. Specifically, for example, indium tin oxide (ITO), indium oxide-tin oxide containing silicon or silicon oxide, indium zinc oxide (IZO), tungsten oxide, and oxide. Examples thereof include indium oxide containing zinc (IWZO). These conductive metal oxide films are usually formed by a sputtering method, but may be formed by applying a sol-gel method or the like.

For example, indium oxide-zinc oxide (IZO) can be formed by a sputtering method using a target in which 1 to 20 wt% of zinc oxide is added to indium oxide. Indium oxide containing tungsten oxide and zinc oxide (IWZO) is formed by sputtering using a target containing 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide with respect to indium oxide. can do. In addition, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium ( Pd), or a nitride of a metal material (for example, titanium nitride).

As the second electrode 205, a metal, an alloy, an electrically conductive compound, a mixture thereof, or the like with a low work function (specifically, 3.8 eV or less) can be used. Specific examples of such a cathode material include elements belonging to Group 1 or Group 2 of the periodic table of elements, that is, alkali metals such as lithium (Li) and cesium (Cs), and magnesium (Mg), calcium (Ca), Examples thereof include alkaline earth metals such as strontium (Sr), alloys containing these (MgAg, AlLi), rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing these.

Next, the peeling layer 201 is dissolved using an etching solution 207 (FIG. 2B). An alkaline solution is used as the etching solution 207. The alkaline solution is preferably a material that can dissolve (etch) the metal material used for the release layer 201. As an example of such an alkaline solution, an ammonia-hydrogen peroxide mixed solution, TMAH (tetramethylammonium hydroxide), a TMAH-hydrogen peroxide mixed solution, and the like can be given.

In the case where a material (for example, tungsten (W)) that does not dissolve in a single metal but dissolves when oxidized is used as the separation layer 201, a material in which hydrogen peroxide is mixed in an etching solution may be used. In the case of using a material (for example, aluminum (Al)) that dissolves in a single metal but does not dissolve when oxidized, it is preferable to use a layer in which hydrogen peroxide is not mixed in an etching solution.

In this manner, by dissolving the peeling layer 201 using the etching solution 207, the EL layer 204 and the second electrode 205 can be formed even if the EL layer 204 and the second electrode 205 have weak adhesion. It is possible to peel from the substrate 200 without peeling at the interface. Further, since the peeling layer 201 can be dissolved, peeling can be performed without bending the manufactured light-emitting element, and the substrate can be reused.

Subsequently, the film 208 is inserted into the region where the release layer 201 is dissolved (FIG. 2C). For the film 208, PEN (polyethylene naphthalate) or the like is used.

Although not shown, actually, when the peeling layer 201 is dissolved using the etching solution 207, the end portions of the element layer 202 and the ultraviolet curable resin 206 are lifted by about several millimeters. The film 208 is inserted into the raised portion.

The peeling layer 201 is removed by moving the film 208 toward a region where peeling does not proceed while adding the etching solution 207 to the region where the peeling layer 201 is dissolved (FIG. 2D). By inserting the film 208 and simultaneously performing the dissolution of the peeling layer 201 using the etching solution 207 and the movement of the film 208, peeling can be performed efficiently without causing bending stress to the light-emitting element.

In the conventional peeling method, even when the peeling layer 201 is dissolved as described in this embodiment mode, when the transfer body 209 using the ultraviolet curable resin 206 as a support is separated from the substrate 200, the transfer body 209 is separated. Needed to bend. In this method, the element layer 202 and the EL layer 204 may be destroyed. In this embodiment mode, the film 208 is moved toward a region where peeling does not proceed and the peeling layer 201 is removed, so that peeling can be performed without bending the element layer 202 or the EL layer 204.

More efficient peeling can be performed by using both the method of dissolving the peeling layer using an etching solution and the method of peeling by moving the film.

Since it is a method of proceeding peeling while adding an etching solution, electrostatic discharge breakdown can be prevented.

In addition, when the adhesion between the substrate and the release layer is weaker than the adhesion between the films in the semiconductor element layer, the separation can be performed only by the process of moving the film without adding an etching solution. Also in this case, peeling can be performed without causing bending stress to the semiconductor element.

Although this embodiment mode describes an active matrix light emitting device, it can also be applied to a passive matrix light emitting device.

Although this embodiment mode describes a light-emitting device, it can be applied to all semiconductor devices that can function by utilizing semiconductor characteristics, such as liquid crystal display devices, semiconductor circuits, and electronic devices.

Note that this embodiment can be implemented in appropriate combination with the structures shown in the other embodiments in this specification or the structures shown in the examples.

(Embodiment 3)
In this embodiment, an ultraviolet curable resin used when peeling a flexible light-emitting device will be described.

The peeling step is performed after a substrate serving as a support is provided above the element layer formed on the substrate and the element layer is held. In the case of a light-emitting device, the light-emitting element deteriorates due to water or oxygen, and dissolves when it comes into contact with an organic solvent. Therefore, it is necessary to devise which material to use in the peeling process.

The ultraviolet curable resin used as the support described in Embodiment Mode 1 can be formed without using a solvent. Further, since it can be manufactured by heat treatment at 80 ° C. or lower, it can be formed without damaging the EL layer.

In the case of manufacturing a light emitting device having a top emission structure, a base material used as a support must also have a high transmittance, but an ultraviolet curable resin is preferable because it has a high transmittance.

Although this embodiment mode describes a light-emitting device, it can be applied to all semiconductor devices that can function by utilizing semiconductor characteristics, such as liquid crystal display devices, semiconductor circuits, and electronic devices.

Note that this embodiment can be implemented in appropriate combination with the structures shown in the other embodiments in this specification or the structures shown in the examples.

(Embodiment 4)
In this embodiment mode, a manufacturing process of a flexible light-emitting device is described with reference to FIGS.

A first buffer layer 301, a separation layer 302, and a second buffer layer 303 are formed over a glass substrate 300 (FIG. 3A). The first buffer layer 301 is formed using an insulating material. As an example of the insulating material, silicon oxynitride or the like can be used.

The peeling layer 302 is formed using a metal material. It is preferable to use a material that is soluble in an alkaline solution as the metal material. As an example of such a metal material, tungsten (W), titanium (Ti), aluminum (Al), or tin (Sn) can be used.

The second buffer layer 303 is formed using an insulating material. As an example of the insulating material, silicon nitride, silicon oxynitride, silicon nitride oxide, or the like can be used. The second buffer layer 303 may be a single layer or a stacked structure, but the total thickness of the second buffer layer 303 is preferably about 1000 nm or more. For example, a structure in which a silicon oxynitride film 600 nm, a silicon nitride film 200 nm, and a silicon oxynitride film 200 nm are sequentially stacked is preferable.

Note that in this specification, silicon oxynitride has a higher oxygen content than nitrogen, and preferably has Rutherford backscattering (RBS) and hydrogen forward scattering. When measured using the method (HFS: Hydrogen Forward Scattering), the concentration ranges from 50 to 70 atomic% for oxygen, 0.5 to 15 atomic% for nitrogen, 25 to 35 atomic% for silicon, and 0.1 for hydrogen. The thing contained in the range of -10 atomic%. Further, silicon nitride oxide has a composition containing more nitrogen than oxygen, and preferably has a concentration range of 5 to 30 atomic% when measured using RBS and HFS. Nitrogen is contained in the range of 20 to 55 atomic%, silicon is contained in the range of 25 to 35 atomic%, and hydrogen is contained in the range of 10 to 30 atomic%. However, when the total number of atoms constituting silicon oxynitride or silicon nitride oxide is 100 atomic%, the content ratio of nitrogen, oxygen, silicon, and hydrogen is included in the above range.

A base insulating film 304 and a crystalline semiconductor film 305 are formed over the second buffer layer 303 (FIG. 3B). As the base insulating film 304, a stacked film of silicon nitride oxide and silicon oxynitride can be used. As the crystalline semiconductor film 305, a crystalline semiconductor manufactured by irradiating an amorphous semiconductor with a laser is used.

The manufactured crystalline semiconductor film 305 is etched to form an island-shaped semiconductor layer 306. Next, a gate insulating film 307 is formed over the exposed base insulating film 304 and the island-shaped semiconductor layer 306 (FIG. 3C). Silicon oxynitride or the like can be used for the gate insulating film 307.

Next, a first gate electrode layer 308 and a second gate electrode layer 309 are formed (FIG. 3D).

Subsequently, the first gate electrode layer 308 and the second gate electrode layer 309 are etched, so that the first gate electrode 310 and the second gate electrode 311 are formed (FIG. 4A). Tantalum nitride can be used for the first gate electrode 310, and tungsten (W) can be used for the second gate electrode 311.

Next, a first interlayer insulating film 312 is formed over the first gate electrode 310 and the second gate electrode 311 (FIG. 4B). The first interlayer insulating film 312 may be a single layer or a stacked structure, for example, a film in which silicon oxynitride, silicon nitride, silicon oxynitride, or the like is stacked.

Next, contact holes are formed in the gate insulating film 307 and the first interlayer insulating film 312. Subsequently, a wiring 313 is formed so as to be electrically connected to the island-shaped semiconductor layer 306 through the contact hole described above (FIG. 4C). The wiring 313 may be a single layer or a laminated structure, and examples thereof include a laminate of titanium (Ti), aluminum (Al), and titanium (Ti) in this order.

Next, a second interlayer insulating film 314 is formed, a contact hole is formed, and a part of the wiring 313 is exposed. Silicon oxynitride is preferably used for the second interlayer insulating film 314. Subsequently, a first electrode layer is formed so as to be electrically connected to the wiring 313 through a contact hole in the second interlayer insulating film 314. The first electrode layer is etched into a desired shape to form a first electrode 315 (FIG. 4D).

As the first electrode 315, a metal, an alloy, a conductive compound, a mixture thereof, or the like with a high work function (specifically, 4.0 eV or more) is preferably used. Specifically, for example, indium tin oxide (ITO), indium oxide-tin oxide containing silicon or silicon oxide, indium zinc oxide (IZO), tungsten oxide, and oxide. Examples thereof include indium oxide containing zinc (IWZO). These conductive metal oxide films are usually formed by a sputtering method, but may be formed by applying a sol-gel method or the like.

For example, indium oxide-zinc oxide (IZO) can be formed by a sputtering method using a target in which 1 to 20 wt% of zinc oxide is added to indium oxide. Indium oxide containing tungsten oxide and zinc oxide (IWZO) is formed by sputtering using a target containing 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide with respect to indium oxide. can do. In addition, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium ( Pd), or a nitride of a metal material (for example, titanium nitride).

A partition wall 316 is formed so as to cover an end portion of the first electrode 315. As the partition wall 316, an organic resin such as polyimide can be used. Next, an EL layer 317 and a second electrode 318 are formed (FIG. 5A).

The EL layer 317 includes a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, a hole blocking layer, and the like. A material used for the EL layer 317 may be selected as appropriate.

As the second electrode 318, a metal, an alloy, an electrically conductive compound, a mixture thereof, or the like with a low work function (specifically, 3.8 eV or less) can be used. Specific examples of such a cathode material include elements belonging to Group 1 or Group 2 of the periodic table of elements, that is, alkali metals such as lithium (Li) and cesium (Cs), and magnesium (Mg), calcium (Ca), Examples thereof include alkaline earth metals such as strontium (Sr), alloys containing these (MgAg, AlLi), rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing these.

An ultraviolet curable resin 319 is applied so as to cover the manufactured light-emitting element (the first electrode 315, the EL layer 317, and the second electrode 318) (FIG. 5B). The ultraviolet curable resin 319 is irradiated with ultraviolet rays to perform temporary curing. Subsequently, main curing is performed by heat treatment. Here, the ultraviolet curable resin 319 improves the mechanical strength of the film to be peeled, and functions as a support for peeling and transposing. However, since the EL layer 317 has low resistance to water and organic solvents, it is necessary to select a material that can be formed without using water or organic solvents. Further, since the EL layer 317 has low heat resistance, a material that is cured by ultraviolet irradiation treatment and heat treatment at about 80 ° C. or lower is used for the ultraviolet curable resin 319 used in this embodiment.

Next, drawing is performed so as to surround the outside of the panel portion 321 using the ultraviolet laser 320 (FIGS. 6A and 7A).

The portion irradiated with the laser is melted, and the melted material is removed, whereby a peeling start point (drawing line) 322 is formed (FIGS. 6B and 7B). The drawing line 322 is preferably formed with a width of about 1 mm. FIG. 7 is a perspective view showing a peeling process of the panel portion in which the light emitting element is manufactured.

After that, the first buffer layer 301, the peeling layer 302, and the second buffer layer 303 around the drawing line are removed by physical means such as a cutter (FIG. 8A). Thereby, the space where the etching solution soaks can be ensured more reliably.

By introducing the etching solution 323 into the drawing line 322, the peeling layer 302 is dissolved and partially lifted off (FIG. 8B). An alkaline solution is used as the etching solution 323. The alkaline solution is preferably a material that can dissolve (etch) the metal material used for the release layer 302. As an example of such an alkaline solution, an ammonia-hydrogen peroxide mixed solution, TMAH (tetramethylammonium hydroxide), TMAH (tetramethylammonium hydroxide) -hydrogen peroxide mixed solution, or the like can be used.

In the case where a material (for example, tungsten (W)) that does not dissolve in a single metal but dissolves when oxidized is used as the peeling layer 302, a material in which hydrogen peroxide is mixed in an etching solution may be used. In the case where a material (for example, aluminum (Al)) that dissolves in a single metal but does not dissolve when oxidized is used as the separation layer 302, a material in which hydrogen peroxide is not mixed in an etching solution may be used.

When tungsten (W) is used for the peeling layer 302 and an ammonia-hydrogen peroxide mixed solution is used for the etching solution 323, the part of the peeling layer 302 that is in contact with the etching solution 323 dissolves in a few seconds. Therefore, adhesion between the separation layer 302 and the first buffer layer 301 or adhesion between the separation layer 302 and the second buffer layer 303 can be weakened, and separation is performed without causing bending stress in the light-emitting element. be able to.

6B to 8B, the drawing line 322 divides the first buffer layer 301, the separation layer 302, the second buffer layer 303, the base insulating film 304, and the ultraviolet curable resin 319 into two. However, for simplification of the drawing, the first buffer layer 301, the peeling layer 302, the second buffer layer 303, the base insulating film 304, and the ultraviolet curable resin 319 on the left side of the drawing line are omitted in FIG. I decided to.

In the region 324 where the lift-off has progressed, a gap is generated between the glass substrate 300 and the second buffer layer 303. A film 325 is inserted into the gap (FIG. 9A).

Although not shown, in practice, when the peeling layer 302 is dissolved using the etching solution 323, the end of the ultraviolet curable resin 319 is lifted by about several millimeters. A film 325 is inserted into the raised portion.

By moving toward the region 326 where peeling has not progressed while adding the etching solution 323, the lift-off region is widened (FIG. 9B). As the film 325 to be inserted, for example, PEN (polyethylene naphthalate) or the like can be used.

When the peeling is completed, the attached etching solution is washed with pure water. Through the above steps, a flexible light-emitting device can be manufactured. Note that as the solution for cleaning the etching solution, any solution that can clean the etching solution may be used.

Colorization of the light emitting device is performed by aligning pixels and separately applying light emitting materials that emit red (R), green (G), and blue (B), or by forming a colored layer (color filter). When peeling is performed to make the light emitting element flexible, problems such as bending of the surface to be formed, shrinkage, and the like occur, so that alignment is difficult. In this embodiment mode, an EL layer, a colored layer (color filter), and the like can be formed before the peeling step, and thus can be easily applied to colorization. Further, in the case where a peeling step is performed in the middle of the manufacturing process, the transposition needs to be performed at least twice. However, the manufacturing method described in this embodiment has an advantage that the number of steps is short and the manufacturing is easy.

Moreover, since it is a method of advancing peeling while adding etching liquid, electrostatic discharge destruction can also be prevented.

In addition, when the adhesiveness inside the peeling layer is weaker than the adhesiveness between the films in the semiconductor element layer, the peeling can be performed only by the process of moving the film without adding an etching solution. Also in this case, peeling can be performed without causing bending stress to the semiconductor element.

Although this embodiment mode describes an active matrix light emitting device, it can also be applied to a passive matrix light emitting device.

Although this embodiment mode describes a light-emitting device, it can be applied to all semiconductor devices that can function by utilizing semiconductor characteristics, such as liquid crystal display devices, semiconductor circuits, and electronic devices.

Note that this embodiment can be implemented in appropriate combination with the structures shown in the other embodiments in this specification or the structures shown in the examples.

In this embodiment, an etching rate when the peeling layer (tungsten (W)) is etched with an etching solution (ammonia-hydrogen peroxide mixed solution) will be described.

First, tungsten (W) 50 nm was formed on a glass substrate. Next, (A) hydrogen peroxide solution: ammonia water: water = 5: 2: 2 mixed as an etching solution, (B) hydrogen peroxide solution: ammonia water: water = 5: 2: 0 mixed. Wet etching was performed by dipping using the solution. The concentration of hydrogen peroxide water is 34.5%, and the concentration of ammonia water is 28%. The results are shown in Table 1.

From Table 1, it was found that the mixed solution (B) not diluted with water had an etch rate about 1.3 times that of the mixed solution (A) diluted with water. From these results, in one embodiment of the present invention, a mixed solution not diluted with water was used as an etching solution.

Note that this embodiment can be implemented in appropriate combination with the structures shown in the other embodiments in this specification or the structures shown in the embodiments.

In this example, a manufacturing process of a flexible light-emitting device will be described with reference to FIGS.

A silicon oxynitride film was formed to a thickness of 100 nm on the glass substrate 300 by a CVD method, and the first buffer layer 301 was obtained. Subsequently, a tungsten (W) film was formed with a thickness of 50 nm, a silicon oxynitride film with a thickness of 600 nm, a silicon nitride film with a thickness of 200 nm, and a silicon oxynitride film with a thickness of 200 nm. The tungsten (W) film was provided as the separation layer 302, and the other films were provided as the second buffer layer 303 (FIG. 3A). At this time, the total film thickness of the second buffer layer 303 needs to be 1000 nm or more. This is to prevent the peeling surface from moving to the EL layer.

A silicon nitride oxide film 140 nm and a silicon oxynitride film 100 nm were formed as a base insulating film 304 over the second buffer layer 303.

Next, a crystalline semiconductor film 305 was formed (FIG. 3B). As the semiconductor layer, an amorphous semiconductor, a crystalline semiconductor, a microcrystalline semiconductor, or the like can be used. In this embodiment, a crystalline semiconductor manufactured by irradiating a laser to an amorphous semiconductor is used.

The manufactured crystalline semiconductor film 305 is etched to form an island-shaped semiconductor layer 306. Next, a gate insulating film 307 was formed (FIG. 3C). Silicon oxynitride 110 nm was formed as the gate insulating film 307.

Next, tantalum nitride was formed to a thickness of 30 nm as the first gate electrode layer 308, and tungsten (W) was formed to a thickness of 370 nm as the second gate electrode layer 309 (FIG. 3D).

Subsequently, the first gate electrode layer 308 and the second gate electrode layer 309 were etched to form the first gate electrode 310 and the second gate electrode 311 (FIG. 4A).

Next, a first interlayer insulating film 312 was formed over the first gate electrode 310 and the second gate electrode 311 (FIG. 4B). The first interlayer insulating film 312 was formed by sequentially stacking silicon oxynitride 50 nm, silicon nitride oxide 140 nm, and silicon oxynitride 520 nm.

Next, contact holes were formed in the gate insulating film 307 and the first interlayer insulating film 312. Subsequently, a wiring 313 is formed so as to be electrically connected to the island-shaped semiconductor layer 306 through the contact hole described above (FIG. 4C). The wiring 313 may be a single layer or a stacked structure. In this embodiment, the wiring 313 is stacked in the order of titanium (Ti) 100 nm, aluminum (Al) 700 nm, and titanium (Ti) 100 nm.

Next, 150 nm of silicon oxynitride was formed as the second interlayer insulating film 314. Subsequently, a part of the wiring 313 was exposed by forming a contact hole.

A first electrode layer was formed so as to be electrically connected to the wiring 313 through a contact hole in the second interlayer insulating film 314. As the first electrode layer, ITSO (ITO containing SiO ₂ ) was formed to a thickness of 125 nm. The first electrode layer was etched to form the first electrode 315 (FIG. 4D).

A partition wall 316 made of polyimide was formed so as to cover the end portion of the first electrode 315. Next, an EL layer 317 and a second electrode 318 were formed (FIG. 5A).

The EL layer 317 includes a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, a hole blocking layer, and the like. A material used for the EL layer 317 may be selected as appropriate. In this embodiment, NPB (4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl) and Molybdenum oxide composite layer 50 nm, NPB 10 nm as the hole transport layer, Alq (tris (8-quinolinolato) aluminum) and coumarin 6 as the light emitting layer 40 nm by co-evaporation, Alq 10 nm as the electron transport layer, electron injection As a layer, Alq and cesium carbonate were deposited to 20 nm by co-evaporation. Aluminum (Al) was used for the second electrode. In addition, Alq of a light emitting layer is a host material, and coumarin 6 is a guest material.

An ultraviolet curable resin 319 was applied with a thickness of 150 μm with a bar coater so as to cover the manufactured light-emitting element (the first electrode 315, the EL layer 317, and the second electrode 318) (FIG. 5B). As the ultraviolet curable resin 319, an acrylic-urethane resin (Norland NEA121) was used. An acrylic-urethane resin can be fired at a low temperature of 80 ° C. or lower and has a visible light transmittance of 90% or more, and thus can be said to be a material suitable for manufacturing a light-emitting device.

Next, ultraviolet rays (wavelength: 365 nm) were irradiated at 20 mW / cm ² for 3 minutes to perform temporary curing. Subsequently, main curing was performed by applying heat treatment at 80 ° C. for 3 hours while applying a pressure of 0.5 MPa with a press.

Next, using an ultraviolet laser 320 (wavelength: 266 nm, output: 1.8 W), drawing was performed so as to surround the outside of the region (panel portion) 321 to be a panel (FIGS. 6A and 7A). .

Since the portion irradiated with the laser melts, a peeling start point (drawing line) 322 can be formed (FIGS. 6B and 7B). The drawing line 322 was formed with a width of about 1 mm.

After that, the first buffer layer 301, the peeling layer 302, and the second buffer layer 303 around the drawing line 322 were cut with a cutter (FIG. 8A). Thereby, the space into which the ammonia-hydrogen peroxide mixed solution enters can be ensured more reliably.

Next, an etching solution 323 was introduced into the drawing line 322. As the etching solution 323, an ammonia-hydrogen peroxide mixed solution was used. The release layer that touched the etching solution 323 dissolved in a few seconds and was partially lifted off (FIG. 8B).

6B to 8B, the drawing line 322 divides the first buffer layer 301, the separation layer 302, the second buffer layer 303, the base insulating film 304, and the ultraviolet curable resin 319 into two. However, for simplification of the drawing, the first buffer layer 301, the peeling layer 302, the second buffer layer 303, the base insulating film 304, and the ultraviolet curable resin 319 on the left side of the drawing line are omitted in FIG. I decided to.

While adding the etchant 323, the film 325 was inserted into the gap between the glass substrate 300 and the second buffer layer 303 in the region 324 where the lift-off progressed (FIG. 9A). In this example, a PEN (polyethylene naphthalate) film (thickness: 50 μm) was used as the film 325.

Although not shown, in practice, when the peeling layer 302 is dissolved using the etching solution 323, the end of the ultraviolet curable resin 319 is lifted by about several millimeters. A film 325 was inserted into the raised portion.

When the film 325 was moved toward the region where peeling did not proceed (region where lift-off did not proceed) 326, the lift-off region expanded and the peeling layer could be removed (FIG. 9B).

After the completion of peeling, the adhering etching solution was washed with pure water. Through the above steps, a flexible light-emitting device was able to be manufactured.

Colorization of the light emitting device is performed by aligning pixels and separately applying light emitting materials that emit red (R), green (G), and blue (B), or by forming a colored layer (color filter). When peeling is performed and the light emitting element is made flexible, problems such as curvature of the surface to be formed, shrinkage, and the like occur, so that alignment is difficult. In this embodiment, since an EL layer, a colored layer (color filter), and the like can be formed before the peeling step, it can be easily applied to colorization. Further, in the case where a peeling process is performed in the middle of the manufacturing process, the transposition needs to be performed at least twice. However, the manufacturing method shown in this embodiment has an advantage that the number of processes is short and the manufacturing is easy.

In addition, since it is the method of advancing peeling while adding etching liquid, electrostatic discharge destruction can also be prevented.

In this embodiment, the active matrix light-emitting device has been described. However, the present invention can also be applied to a passive matrix light-emitting device.

Although this embodiment has been described with reference to a light-emitting device, it can be applied to all semiconductor devices that can function by utilizing semiconductor characteristics, such as liquid crystal display devices, semiconductor circuits, and electronic devices.

Note that this embodiment can be implemented in appropriate combination with the structures shown in the other embodiments in this specification or the structures shown in the embodiments.

In Example 2, a groove (opening) for inserting a film used for peeling was a drawing line 322 formed by a laser. However, one embodiment of the present invention is not limited to this method. In this embodiment, a forming method different from the groove forming method described in Embodiment 2 will be described with reference to FIGS.

Using an ultraviolet laser 1220 (wavelength: 266 nm, output: 1.3 to 1.8 W), a drawing line 1222 is formed so as to surround the outside of the region 1221 to be a panel and to expose the peeling layer. A drawing line 1223 was formed so as to surround the drawing line 1222 and to expose the release layer. That is, a double drawing line is formed outside the region 1221 which becomes a panel. A region 1224 to be removed later is provided between the drawing line 1222 and the drawing line 1223. The interval between the drawing line 1222 and the drawing line 1223 is preferably about 0.5 to 2 mm. The widths of the drawing lines 1222 and 1223 are each preferably about 0.05 to 0.1 mm. In this embodiment, the interval between the drawing lines 1222 and 1223 is 0.8 mm, and the widths of the drawing lines 1222 and 1223 are 0.1 mm.

Next, the region 1224 to be removed was removed with a cutter or the like. As a result, a groove 1225 in which the release layer was exposed was formed. The width of the groove 1225 is desirably about 1 to 2 mm. In this embodiment, the width of the groove 1225 is 1 mm.

Next, an etching solution was introduced into the groove 1225. As a result, the release layer that touched the etching solution was dissolved and partially lifted off. Next, a film was inserted into the portion where the lift-off progressed while adding the etching solution. That is, the film was inserted into the dissolved release layer. The film may use an organic resin such as film-like polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polyethersulfone (PES). In this example, a PEN film (thickness: 50 μm) was used as the film.

In this example, a double drawing line was formed using the ultraviolet laser 1220 and the groove 1225 was formed, so that a sufficient space for inserting the film into the release layer could be secured. Further, since the peeling layer is exposed in the region of the groove 1225, no other process is required, and the etching solution can be in contact with the peeling layer only by introducing the etching solution into the groove 1225.

Note that this embodiment can be implemented in appropriate combination with the structures shown in the other embodiments in this specification or the structures shown in the embodiments.

A passive matrix type flexible light emitting device was fabricated according to Example 2.

FIG. 10A shows a flexible light-emitting element that has a first end and a second end by hand, and the distance between the first end and the second end is reduced to about 3 to 5 cm. It is the photograph which light-emitted in the state which bent the light emitting element. FIG. 10B is a photograph of light emitted in a state of being attached to a cylindrical plastic substrate having a diameter of 73 mm.

In this example, an electronic device in which the flexible light-emitting device obtained in Embodiments 1 to 4 and Examples 1 to 4 is incorporated in a display portion will be described. Electronic devices that can incorporate the flexible light-emitting device of one embodiment of the present invention include a video camera, a digital camera, a head-mounted display (goggles display), a car navigation system, a projector, a car stereo, a personal computer, a portable information terminal, and An electronic book etc. are mentioned. An example is shown in FIG.

FIG. 11A illustrates a television device, which includes a housing 2010, a keyboard portion 2012 that is an operation portion, a display portion 2011, a speaker portion 2013, and the like. One embodiment of the present invention is applied to manufacturing the display portion 2011. Since the display portion in FIG. 11A uses a flexible light-emitting device that can be bent, the display portion is a television device having a bent display portion. Since the shape of the display portion can be freely designed as described above, a television device having a desired shape can be manufactured.

Note that one embodiment of the present invention is not limited to a television device, and can be used as a display medium such as a personal computer monitor, an information display board at a railway station or an airport, or an advertisement display board in a street. Can be applied.

FIG. 11B illustrates a portable information terminal (electronic book), which includes a main body 3001, display portions 3002 and 3003, a storage medium 3004, operation switches 3005, an antenna 3006, and the like.

DESCRIPTION OF SYMBOLS 100 Substrate 101 Peeling layer 102 Semiconductor element layer 103 UV curable resin 104 Etching solution 105 Film 106 Transfer body 200 Substrate 201 Peeling layer 202 Element layer 203 First electrode 204 EL layer 205 Second electrode 206 UV curable resin 207 Etching solution 208 Film 209 Transposed body 300 Glass substrate 301 First buffer layer 302 Release layer 303 Second buffer layer 304 Base insulating film 305 Crystalline semiconductor film 306 Island-like semiconductor layer 307 Gate insulating film 308 First gate electrode layer 309 Second Gate electrode layer 310 first gate electrode 311 second gate electrode 312 first interlayer insulating film 313 wiring 314 second interlayer insulating film 315 first electrode 316 partition 317 EL layer 318 second electrode 319 UV curing Resin 320 UV laser 321 Panel 321 panel portion 322 drawing line 323 etchant 324 liftoff not advanced the advanced region 325 film 326 peeled area 2010 housing 2011 display portion 2012 keyboard unit 2013 Speaker 3001 body 3002 display unit 3004 a storage medium 3005 operation switches 3006 Antenna

Claims (7)

Forming a release layer on the substrate,
Forming a semiconductor element on the release layer;
Forming a resin layer on the semiconductor element;
Dissolve the release layer using an etchant,
Insert the film into the dissolved area of the release layer,
A method for manufacturing a flexible semiconductor device , wherein the substrate and the semiconductor element are separated by moving the film toward an undissolved region of the release layer . Forming a release layer on the substrate,
Forming a buffer layer on the release layer;
Forming a semiconductor element on the buffer layer;
Forming a resin layer on the semiconductor element;
Dissolve the release layer using an etchant,
Insert the film into the dissolved area of the release layer,
A method for manufacturing a flexible semiconductor device , wherein the substrate and the semiconductor element are separated by moving the film toward an undissolved region of the release layer . In claim 1 or 2,
Irradiating a laser so as to surround the semiconductor element, forming a groove in the resin layer,
A method for manufacturing a flexible semiconductor device, wherein the release layer is dissolved along the groove using the etching solution. In any one of Claims 1 thru | or 3 ,
The method for manufacturing a flexible semiconductor device, wherein the film is polyethylene naphthalate. In any one of Claims 1 thru | or 4 ,
The method for manufacturing a flexible semiconductor device, wherein the etching solution is an ammonia-hydrogen peroxide mixed solution. In any one of Claims 1 thru | or 5 ,
The method for manufacturing a flexible semiconductor device, wherein the resin layer is formed of an ultraviolet curable resin. In any one of Claims 1 thru | or 6 ,
The method for manufacturing a flexible semiconductor device, wherein the release layer contains tungsten.